In preparation for a series of publications on the pleurothallid genera of Brazil, twenty-four new species have been discovered. They are described and illustrated here. Two new species, Acianthera klingelfusii and Anathallis johnsonii, are described for Argentina, the former also occurring in Brazil. The other 22 species are exclusively Brazilian in distribution. They are listed here in generic alphabetical order: Anathallis crassapex, A. dantasii, A. gutfreundii A. paula, A. pilipetala, A. seidelii, A. velvetina, Pabstiella acrogenia, P. analoga, P. capijumensis, P. decurva, P. discors, P. freyi, P. gossameri, P. lacerticeps, P. melior, P. nymphalis, P. osculator, P. quasi, P. sansonii, P. savioi, and Specklinia erecta. Eleven new combinations are proposed in the Brazilian Pleurothallidinae: Pabstiella bicolor, P. colorata, P. diffusiflora, P. dracula, P. ochracea, P. pantherina, P. punctata, P. purpurea, P. seriata, P. viridula, and Specklinia barbosae.